There are advantages in being able to provide phone users information based on their location. If the location of the phone user is known, then information about the nearest product or service can be provided (for example the cheapest gas station within a certain distance). Furthermore, advertisements can be targeted with precision, i.e. based on where the recipient of the advertisement is likely to be in the near future.
There are a number of systems in place for determining the location of a cellular phone user. For example the company known as Cell-Loc, Inc. provides a service to identify the location of cellular phone users. This system uses of triangulation, i.e. three receivers must receive the signal from the cellular phone in order to determine the location of the phone. This requires that three such receivers be in range of the telephone, which in turn has a certain expense. Furthermore, such a system will only work on phones that function as transmitters, i.e. cellular phones, and will not work with other phones. Another location based system is the GPS systems to locate the user. This requires satellites and the enormous cost inherent in providing same.
Systems which store geographic information commonly in use today store and index information by postal code or geographic longitude or latitude coordinates. Geographic Information Systems (GIS) provide spatial processing functionalities and are based on the minimal unit of longitude and latitude coordinates. Such systems build lines and polygons and perform computations and transformation on longitude and latitude coordinates. The user interface for such systems is generally a personal computer. Such systems are commonly used for thematic mapping, radio wave propagation studies, and transport infrastructure design.